Mars Exploration Rover Mission
Cumberland Ridge Rocks: Summary
•A layered stratigraphic section several meters thick
•Enormous variety in texture:
–Massive
–Finely laminated
–Globular
•Consistent geochemical “fingerprint” through all rocks:
–High Ti
–High P
–Low Cr
•Substantial range in degree of alteration:
–Fe3+/FeTotal = 0.4 to 0.95; the most-heavily altered rocks contain goethite
–Alteration varies both vertically and laterally
•Interpretation:
–An aqueously-altered volcaniclastic succession. May include both pyroclastics and their reworked equivalents.
–Phosphorous content is independent of degree of alteration, so the phosphorous is probably primary rather than secondary.